This invention relates to a condensate drain system for installation in a furnace. More particularly, the invention relates to a condensate drain system that has a dual blower and condensate collection housing installed to provide a single drain system to accomplish what heretofore has required, typically, three drains.
A high efficiency furnace incorporates a primary heat exchanger and a secondary heat exchanger. Products of combustion from a burner are caused by a blower to flow serially through the primary heat exchanger and the secondary heat exchanger. If the blower is an induction blower, the products of combustion flow from the secondary heat exchanger to a collector box and from there through the blower to an exhaust flue.
Although the products of combustion remain essentially in a gaseous state all the way through the primary heat exchanger, the purpose of the secondary heat exchanger is to act as a condenser to condense water from the combustion products. Therefore, exiting from the secondary heat exchanger into an outlet manifold are combustion products in a gaseous state mixed with water. Some of the water falls from the combustion gas to the bottom of the outlet manifold, while some of the water remains entrained in the combustion gas that flows to the collector box. While the combustion gas is in the collector box before being drawn into the blower, an additional amount of condensation falls from the air to the bottom of the collector box, but some condensation remains entrained in the combustion gas that flows through the blower and on to the exhaust flue. In the exhaust flue, more of the condensate falls from the combustion gas toward the lower end of the flue.
It is necessary that all this condensate be collected and discharged from the furnace. To handle the various collections of condensate in the condenser outlet manifold, the blower, and the exhaust flue, it has been customary to connect condensate tubing to each piece of equipment that collects the condensate. Typically, a tube is connected to the bottom of the outlet manifold from the condenser, another tube is connected from the bottom of the collector box, and still another tube is connected from the lower end of the exhaust flue. These tubes are individually fed to a suitable drain, such as a floor drain, or sometimes are connected to a common condensate trap which is then connected by another tube to the floor drain. Either arrangement results in three tubes from three sources of condensate and with their respective connections. These tubes are unsightly and often obstruct access to other furnace components. Also, there is danger in their coming disconnected and dripping condensate onto electrical contacts. Further, the multiplicity of tubes compounds leakage possibilities which can lead to rusting of components and the multiplicity of tubes adds to the cost of the furnace. Pursuant to the present invention, this multiplicity of tubes is replaced by a drain system that requires only a single tube.